Hydroxyurea for the treatment of sickle cell anemia.

There are about 50,000 people in the United States who are homozygous for the sickle hemoglobin gene and thus have sickle cell anemia. Sickle cell anemia is primarily seen in persons of African heritage, about 1 in 14 of whom is an asymptomatic carrier (a heterozygote). One in 700 newborns of African heritage is affected.1 Although it is the most severe of the common sickle cell diseases (which include hemoglobin SC disease and sickle β0-thalassemia), patients with sickle cell anemia have a wide spectrum of clinical manifestations. All patients with this disorder have a chronic hemolytic anemia, but the rates of the most common acute vaso-occlusive events (acute painful crises and the acute chest syndrome) vary considerably.2,3 Other common complications include stroke, chronic lung disease, avascular necrosis, and leg ulcers. Health-status surveys suggest that patients with sickle cell anemia have a low quality of life, similar to that of patients with arthritis or myocardial infarction.4 Before the era of hydroxyurea, the average life expectancy was in the 40s.5 In 2004, there were about 113,000 hospitalizations for sickle cell disease in the United States, about 75% of which were for adults. Total hospital costs were about $488 million.6